ABSTRACT
Many reviews and descriptions of original outbreaks have established the typical signs, symptoms, and clinical evolution of Legionnaires' disease, as well as increasing our appreciation of an ever-widening spectrum of atypical manifestations. The typical patient with Legionnaires' disease will seek medical attention after several days of symptoms and often be hospitalized by the 4th or 5th day of illness. Consequently, the bulk of published data on physical findings, laboratory studies, and radiographs is drawn from this stage of involvement. Legionnaires' disease has occurred in association with episodes of appendicitis and pancreatitis; although not etiologically related, these instances serve to remind the clinician that abdominal symptoms may be clues to subdiaphragmatic processes in patients with respiratory illnesses of any etiology. Acute bacterial pneumonia, as typified by pneumococcal infection, accounts for at least 30 to 50% of pneumonias and is clinically distinct from atypical pneumonitis.
